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Bureau of Mines / Minerals yearbook: Metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)

Petkof, Benjamin
Mica,   pp. 783-791 ff. PDF (752.3 KB)


Page 791

 MICA 791 
 Crude mica production, based on exports plus consumption, increased slightly
from 35,119 tons in 1971 to 37,299 tons in 1972. Exports also increased from
26,319 tons valued at $21.7 million in 1971 to 27,949 
tons valued at $25.3 million in l972. Thirty-two percent of exports in both
1971 and 1972 consisted of sheet mica. The remainder consisted of other forms
of processed and scrap mica. 
TECHNOLOGY 
 The work of the Bureau of Mines in the area of recovery of mica concentrates
by flotation from weathered mica pegmatites and micaceous schist ores has
been reviewed. The acid cationic and alkaline anionic-cationic method for
the recovery of coarse and fine mica, respectively, are discussed and flowsheets
-for their use were provided. In addition, mining, recovery, and grinding
of mica were discussed.2 
 Batch laboratory scale tests were run on several industrial minerals -that
included mica to determine the optimum grinding constants. The test used
an attrition grinding process developed previously by the Bureau of Mines.3
 A method has been developed -to break apart natural, synthetic, or mixtures
of mica by initially heating the material to drive off the water of hydration.
The heated -material is then broken apart in oi-iented streams of an inert
gas such as argon to produce thin, smooth-surfaced particles, or flakes with
a high specific surface area and a high ratio of length to thickness.4 
 2Browning, James S. Mica Beneficiation. EuMines Bull. 662, 1973, 21 pp.
 ' Stanczyk, Martin H., and I. L. Feld. Ultrafine Grinding of Several Industrial
Minerals by the Attrition Grinding Process. BuMines RI 7641., 1972, 25 pp.
 4 Ruzikk, 3. Ultradisintegration of Natural or Synthetic Mica. U.S. Pat.
3,719,329, Mar. 6, 1973. 


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